GB656213A - Improvements relating to illuminated signs - Google Patents

Abstract

656,213. Signs. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., SHEPPARD, E. A., and STEVENS, S. A. Aug. 18, 1949, No. 26758/48. [Classes 3(i) and 3(ii)] An edge-illuminated sign comprises a number of different superposed indications on one or more transparent plates each indication being delineated by one or more sets of concentric grooves, the light source for illuminating each set being situated substantially at the common centre thereof. In one form, Fig. 7, the sign comprises a plurality of superposed transparent sheets a each of which carries a different symbol on its back or face. The symbols are formed of concentric V-section grooves, Fig. 9, the included angles between the sides being approximately 50 degrees and the side furthest away from the source of illumination being perpendicular to the face of the transparent sheet. The sheets have a plurality of aligned holes in which lamps are positioned and each sheet is selectively illuminated by either one or two lamps. The sheets which are not to be illuminated by a given lamp or lamps are masked by an opaque tube l, Fig. 7, in each lamp hole f; the grooves on each plate are arranged concentrically with respect to the lamp or lamps for illuminating them; when two lamps are used the grooves are in two sets. The illuminated edge of the plate may be at an angle to the surface of the plate as shown in Fig. 7 or may be perpendicular; in the latter case the lamp filament is arranged in the plane of the plate. In a modification, Fig. 2, more than one indication is carried by a single-plate, the grooves for the indications being arranged to cross at an angle as shown; up to four indications on one plate are described as possible. The grooves are arranged concentrically with respect to the lamp or lamps which illuminate them; thus lamps f1 and f1<SP>1</SP>, Fig. 2, illuminate grooves p and p<SP>1</SP> respectively of one indication and lamps f2 and f2' illuminate grooves q and q<SP>1</SP> of the second indication. Opaque screens may be positioned in slots cut into the plate between the lamps to prevent unwanted reflections. Indications in a plurality of colours are.possible by illuminating sets of grooves in different colours simultaneously by means of colour filters, each indication being composed of more than one set of grooves either on one or more plates. The application to a changeable railway sign consisting of a red bar on a white circular background is described, the bar having two alternative positions, i.e. either horizontal or at a 45 degrees angle; four sets of grooves are used either on one or two plates, two sets being illuminated simultaneously, one white and the other red, the change in the bar position being accomplished by illuminating the other sets of grooves instead of the first two sets.